zoneContentionRuleName

@set:KSLStringControl(allowedValues = ["FIFO", "LoadedFirst"], comment = "Which waiting transporter is let into a zone when it frees")
var zoneContentionRuleName: String(source)

The contention rule by name, so a scenario or an app can change it without holding a rule object. Reading it reports the rule's own toString when the rule is one no name stands for.